Nataraj is the first vegan Indian restaurant that opened its shop in 1989 in Japan.

They focus really on its ingredients.
Its spices are all hand-made by the chef.
It owns 3 organic farms and all the vegetables offered here are from their farms.
Nan is made from domestic flour and natural yeast.
Colza oil is made by traditional way of pressurization and it is GM free.

If I add only one point for vegan, milk are used for some menus.
But you can easily find it as menu shows which one has milk or not.
So all the types of people from vegetarian, vegan to halal they can offer the service.

Nataraj also has its restaurant in Ginza and Ogikubo.
Nataraj Ginza is the chief restaurant of Nataraj.
Here are the links.